Relational Grammar had its beginnings in the early 1970s. In this theory of the structure of language grammatical relations are taken to be `undefined primitives'. The set of relations recognised includes subject, direct object, indirect object and a number of `oblique' relations including benefactive, locative and instrumental. This is the first book that describes the theory's basic ideas, evaluates them and compares them with other approaches in other theories. The treatment is straightforward, and should be comprehensible to anyone conversant with traditional grammatical terminology. All unfamiliar terms and conventions are explained and illustrated. The book is written for students of modern theories of grammar, but it should also be of relevance and interest to descriptive and comparative linguistics. It contains a wealth of data on morphology and syntax and also includes comparisons of Relational Grammar analyses with those of 'non-aligned' linguistics who are working with much the same data.